Methanolysis of 2,4-Dinitrophenyl p-Toluene Sulphonate

Abstract

THE methanolysis of 2,4-dinitrophenyl p-toluene sulphonate has been investigated, in continuance of a series of investigations of the methanolysis of nitrophenyl esters^1,2 both under initially neutral conditions and in the presence of tertiary bases, namely, pyridine and its methyl derivatives. In the cases of picryl acetate¹ and 2,4-dinitrophenyl acetate² both the neutral and base-catalysed reactions show acyl–oxygen fission: . In the case of picryl benzoate¹ under initially neutral conditions, along with acyl–oxygen fission (1), there also occurred some aryloxygen fission (2): Reaction (2) did not, however, occur in the presence of tertiary bases. The order of the catalytic constants ($k_{{\text{2}}^B}$) are in each case $k_{{\text{2}}^{Py}}$ > $k_{2^{\mathit{\text{Co}}}}$ >$k_{2^{\mathit{\text{Lu}}}}$ > $k_{{\text{2}}^{Pi}}$, whereas the basic strengths are in the order 2,4,6-collidine > 2,6-lutidine > 2-picoline > pyridine. Thus specific and general base catalysis are ruled out. The mechanism is thus nucleophilic catalysis.